I think you might be right and I might be trying to do this a little too fast.

Kayb said he was able to do it right at 70
Most multi-box friendly heroic?

But for some reason I can’t figure it out. I have given it around 15 tries doing every strat I could find/think of, the best I could do it 20%.
I've given up for now. Hopefully I can come back and figure it out once I get a bit more gear.